Biodiversity gain sites in England are locations where new or improved habitats are created to achieve England's Biodiversity Net Gain (BNG) requirement. Developers must now achieve at least a 10% increase in the biodiversity of a parcel of land following its development. If this is not possible within the development site itself - by creating or enhancing its existing habitats - the biodiversity gain must be delivered elsewhere, by developers paying for the same types of habitat at a different location. For this purpose, Biodiversity Gain Sites (BGS) have been made available by landowners, who will sell biodiversity units to developers.
You can search the list of sites here in various ways to find the most appropriate one for your needs.
The data included in the list of biodiversity gain sites given here is compiled from various sources:
Biodiversity Gain Site (BGS) Register
BGS Register Search This is the source of the base data. Until the data is provided publicly in computer-readable form, the data is extracted from the json files used to render the HTML website.
The Biodiversity Gain Site Register Regulations 2024 These are the regulations which govern the establishment and management of Biodiversity Gain Sites. The register operator must ensure that the information in the biodiversity gain site register is accessible to members of the public.
Details of the responsible bodies are taken from the .GOV list Conservation covenants: list of designated responsible bodies.
BGS Site locations are given but the precise location of allocations addresses has to be deduced using the Google Geocoder. Where the address is incomplete or missing, the location falls back to the centre point of the LPA.
The boundaries of all the English LPAs are used to identify the LPA in which a development site or BGS site is located
The boundaries of NCAs are used to identify the NCA in which a development site or BGS site is located.
The boundaries of LNRS sites are used to identify the LNRS in which a development site or BGS site is located
Deprivation refers to people's unmet needs, a lack of access to opportunities and resources which we might expect in our society.
LSOAs are small areas designed to be of a similar population size, with an average of approximately 1,600 residents or 650 households. There are 33,755 LSOAs in England. They are a standard statistical geography and were produced by the Office for National Statistics for the reporting of small area statistics. LSOAs are referred to as 'neighbourhoods' .
Deprivation in England (2025)..
A decile is calculated by ranking the 33,755 neighbourhoods in England from most deprived to least deprived and dividing them into 10 equal groups (i.e. each containing 3,375 or 3,376 neighbourhoods). These deciles range from the most deprived 10 per cent of neighbourhoods nationally to the least deprived 10 per cent of neighbourhoods nationally.
We enhanced the base data extracted from the BGS register in a number of ways:
Baseline parcels are as per the standard formula – Habitat Unit (HU) = Habitat area/length (of parcel) x Distinctiveness (of Habitat) x Condition (of parcel) x Strategic Significance (where SS is set to Low, 1).
Created habitat parcels - HU = Habitat area/length (of parcel) x Distinctiveness (of Habitat) x Condition (of parcel) x Strategic Significance (of parcel – low, 1) x Temporal Risk (of Habitat and Condition) x Difficulty factor (of the Habitat) x Spatial Risk (Low, 1)
Enhanced habitat parcels - HU = ((((Enhanced Size x Enhanced Distinctiveness x Enhanced condition)-(Enhanced Size x Baseline Distinctiveness x Baseline Condition)x(Time to Target Multiplier x Difficultly Multiplier)+(Enhanced Size x Baseline Distinctiveness x Baseline condition))x Enhanced Strategic significance multiplier.
Habitat Unit gain is calculated by subtracting the baseline parcel's HU from the improved parcel's HU.
Constraint Rules: We base our allocation on the BNG Statutory Metric definitions: 'Enhanced' requires either an increase in Condition of the same habitat, or an increase in Distinctiveness within the same broad habitat type. 'Creation' generally requires a change in broad habitat type, though we treat a large distinctiveness increase from a Low/Very Low baseline as 'Creation' to align with the data.
Despite the limitations of the source data, we think this way of viewing the data gives you a good overview of how a site has become a biodiversity gain site.
We refresh Defra's BGS data every 6 hours.
Digital boundaries and reference maps:
© Natural England 2023. Contains OS data © Crown Copyright [and database right] 2023
Contains GeoPlace data © Local Government Information House Limited copyright and database right 2023
The site summary is now available as a WFS map layer on the WFS service https://bristoltrees.space/wfs/wfs-server.xq?SERVICE=WFS&REQUEST=GetCapabilities.
This is an open-source project designed and built by Bristol Tree Forum using Next.js.
It is based on data sourced from Natural England's Biodiversity gain sites register.
You can view the source code at GitHub.
The data controller responsible for this website is:
Mark Ashdown, Acting Chair, Bristol Tree Forum
Email: BGS_Enquiries@bristoltreeforum.org
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